Mortuary + Blasting Station + Bolas's Citadel + Ornithopter

Mortuary

Blasting Station

Bolas's Citadel

Ornithopter

How it works

1. Activate Blasting Station by tapping it and sacrificing Ornithopter
2. When Ornithopter dies, Mortuary triggers, putting Ornithopter from your graveyard onto the top of your library.
3. Resolve the Blasting Station ability.
4. Cast Ornithopter from the top of your library by paying 0 life.
5. When Ornithopter enters, Blasting Station triggers, untapping Blasting Station.
6. Repeat.

This elegant loop turns the zero-mana cost of Ornithopter into a lethal engine by leveraging Bolas's Citadel to cast it directly from the top of your library for free—costing zero life since its mana value is zero. As you sacrifice the flyer to Blasting Station, Mortuary acts as the glue that immediately redirects it back to the top of your library instead of letting it rest in the graveyard. Finally, every time Ornithopter returns, Blasting Station's triggered ability untaps itself so you can repeat the process indefinitely, turning the revolving door of mechanical insects into an endless storm of damage.